The present disclosure relates to a power-supply control device, the power-supply control device including a transistor that is interposed between a power source and a load as well as a control circuit to which a voltage from the power source is applied and which turns the transistor on or off based on an operating signal for the load that is applied from an external device, and controlling supply of power to the load.
Power-supply control devices that are installed in vehicles and the like and that supply/interrupt power to loads use electromagnetic relays, semiconductor relays, or the like. MOSFETs (metal oxide semiconductor field-effect transistors) that are used as semiconductor relays have high operating-voltage threshold values and may stop operating when the power source voltage is low. Thus, electromagnetic relays that are capable of operating even at a low voltage are used for loads that need the power supply even when the power source voltage is low.
JP 2012-507964T discloses a driver circuit that supplies a load voltage for feeding electricity to a load. The driver circuit includes a feed voltage source for supplying a feed voltage and a temporal storage unit for temporarily storing electrical energy, and the temporal storage unit is connected to the feed voltage source for supplying the electrical energy. Furthermore, it includes a driver unit to which the electrical energy can be supplied by way of the temporal storage unit as necessary, whereby the load voltage can be supplied to the load in the event of a voltage drop of the feed voltage.